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Tuesday, September 11, 2012

Those odd and pesky little facts

So: this is the global temperature trend of the last fifteen years. It is downwards. (Found here)

Now, in and of itself, that doesn't mean very much - it could all be part of the natural fluctuation within an overall increasing trend, etc etc blah blah blah. (Although, obviously, the longer it continues, the more difficult the 'mainstream consensus' will find it to brush things away).

However, what I want to compare and contrast this graph with, is this one, showing use of fuels through the twentieth century (from Gail Tverberg).

Notice how the use of fossil fuels (=oil) really kicked off after the Second World War and that we are now using some four times as much per year as then. Now it occurs to me that if the relationship between the use of fossil fuels and the temperature of the earth was in any way a direct one, then we would be observing a similar acceleration in the year on year increase of temperature as can be seen in the use of fossil fuels. What we observe instead is a contra-indication. Not only is there no acceleration of the increase, there isn't even an increase!

Clearly, carbon dioxide is only one factor in a chaotic system, and there simply isn't a direct and linear relationship between the increase of CO2 in the atmosphere and global temperature change. That's just a pesky little fact.

The interesting question, to my mind, is about how far the increase in temperature in the second half of the twentieth century is anomalous when compared to other periods of history - eg, when compared to the trend since 1700, or the trend since about 1800, or the trend since about 3000 BC. This, however, leads us into Hockey Stick territory - and it explains why that remains such a totem. If the Hockey Stick is correct, then the acceleration can be (just about) found. Yet if the Hockey Stick is fraudulent - which I believe it to be - then this is some strong empirical evidence running against the CAGW hypothesis. I shall maintain my watching brief.

9 comments:

I continue to be amazed how so many people blindly follow the CAGW story without ever checking the evidence. How many more years of no increase in global temperature will it take before the models that insist we are all going to burn will be rejected?

Dear Sam,thank you for the interesting link. Did you look further down to the 150 year data? in particular "Annual air temperature northern hemisphere since 1850". This seems to show a remarkably similar shape to Gail's 'World Energy Consumption'.

The HadCRUT3 dataset is now outdated, something well documented on their webpage.

But a more fundamental point is that we climate scientists (well, I'm a phd student) fully expect the natural internal variability of the climate system to produce hiatuses or "accelerations" in global temperature on yearly to decade timescales. The strength of these oscillations and their spatial structure can deviate substantially from the mean multidecadal to century long trend.

Cherry picking ~10 years of data (starting with a super El Nino) is not a robust analysis of the data, and completely ignores the several decades prior to the selected start point. This analysis therefore is something that might be convincing to an uninitiated reader, but would not contribute to the scientific discussion.

In the end, the real world must obey conservation of energy. The global temperature is effectively a slave to the balance of radiative fluxes into and out of the planet, and as the CO2 concentration rises, the rate at which energy is lost to space will be reduced. The only possible way to rectify this situation is for the planet to increase its temperature in order to respect the planetary energy budget. On short timescales however, one fully expects that cool water might be "mined" from the ocean interior and brought up to the surface, that volcanoes might go off, or that transient oscillations will change cloud cover distribution, causing temporary fluctuations in the global temperature which are decoupled from the mean state.

ccolose - please point me to the temperature data on the last 15 years that you would find acceptableI'm familiar with the cherry-picking argument and, so far as it goes, it is cogent. The question I would ask is: at what point would the continuing trend start to not be explicable in terms of natural variation? When the trend had been in place for ten years, the same cherry-picking argument was made as is now being made at 15 years. Will it be the same at 20 years? I would have much greater sympathy for the cherry picking response if a) it was admitted that *at some point* the trend represented something meaningful, b) someone had said after the 1998 ENSO 'we're not likely to see a significant increase in average temperature for a while = # years or so', and c) this plateau had been predicted by any of the models. So far as I recall the standard CAGW argument for the last 15 years has been to claim 'the temperature will carry on rising' - the longer that it doesn't, the more of a problem it becomes.

Hi Paul - this is from an e-mail I sent to Byron Smith the other day "FWIW I have no doubt that the melting of the Arctic ice is significant, nor that our CO2 emissions are playing a significant part in causing it. As always it's the 'catastrophic' stuff that I'm dubious of - and part of that is rejecting the 'hockey stick' - which is what this graph is [from Nature], essentially. Hence I want to dig down into the how and why a bit more. That is, I'd be surprised if there hadn't been ice-free arctics before, in the last 10,000 years. One of the key contra-indicators for me is that the Antarctic isn't displaying anything like the same sort of behaviour. There is so much that we don't know!" I'm writing an article for Green Christian at the moment which will set out my views in a bit more detail :)

I wonder if you've ever heard of Katharine Hayhoe, a Christian evangelist and climate scientist, living and working here in the states. Below, I've linked to a relatively recent presentation by her. I imagine you two might have an interesting dialogue. Here she's clearly talking to an audience of laypersons. But I imagine she'd welcome a discussion with you, with your interest in, as you say, digging deeper, not to mention what might emerge for either of you within such a discussion as fellow Christians...